1. Field of the Invention
The present invention relates to an epoxy resin composition including silica and core-shell polymer particles. More specifically, the present invention relates to an epoxy resin composition including silica and core-shell polymer particles in which the silica and the core-shell polymer particles whose polarities are different from each other are uniformly dispersed by a polymeric dispersant having a structure in which flexible lipophilic and hydrophilic chains located in the main chain, or an epoxy resin-polymeric dispersant prepolymer, and the polymeric dispersant participates in a curing reaction, achieving improved impact resistance.
2. Description of the Related Art
Epoxy adhesive compositions are reactive adhesive compositions including an epoxy resin, a curing agent, and usually a latent accelerator. Upon heating, the epoxy groups of the epoxy resin react with the curing agent linking epoxy resin compounds by a polyaddition reaction to obtain a cured product.
Such a cured product is known to have good mechanical properties and chemical resistance. Due to these advantages, epoxy adhesive compositions are suitable for the bonding of transportation machinery parts and machine parts. Adhesives for use in such applications are called structural adhesives. Generally, heat-curable epoxy adhesives are used as structural adhesives.
Two-component adhesives as heat-curable epoxy adhesives include two separate components, i.e. a first component including an epoxy resin and a second component includes an epoxy reactive compound. Many two-component epoxy adhesives have been disclosed as structural adhesives for general uses. The two components are previously mixed and undergo thermal curing when a latent curing agent is used.
U.S. Pat. No. 4,728,737 discloses a two-component structural adhesive including an epoxy resin component and a curing agent component.
U.S. Pat. No. 4,916,187 concerns a two-component epoxy resin adhesive composition consisting of a first polyepoxide component and a second curing component including a finely dispersed solid salt of a polyamine and a polyphenol in a liquid adduct.
U.S. Pat. No. 5,629,380 discloses a two-component epoxy adhesive including a first component and a second component wherein the first component includes an epoxy catalyst and an amine curing agent, and the second component includes an epoxy resin having a functionality of more than 1.
U.S. Pat. No. 6,577,971 concerns a two-component epoxy adhesive composition including a first component and a second component wherein the first component includes an epoxy resin and a silane coupling agent, and the second component includes an aliphatic amine and a polyamine.
The above patent documents disclose technologies relating to bicomponent-based epoxy adhesive compositions. However, to our knowledge, there have been no technologies regarding epoxy resin compositions in which silica and core-shell polymer particles whose polarities are different from each other are uniformly dispersed by a polymeric dispersant having lipophilic and hydrophilic chains in the main chain, or an epoxy resin-polymeric dispersant prepolymer, no flowability occurs even at a low viscosity after application to an adherend, and the polymeric dispersant participates in a curing reaction, achieving improved impact resistance.